ssp.c

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/*
 *  linux/arch/arm/mach-pxa/ssp.c
 *
 *  based on linux/arch/arm/mach-sa1100/ssp.c by Russell King
 *
 *  Copyright (C) 2003 Russell King.
 *  Copyright (C) 2003 Wolfson Microelectronics PLC
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 *  PXA2xx SSP driver.  This provides the generic core for simple
 *  IO-based SSP applications and allows easy port setup for DMA access.
 *
 *  Author: Liam Girdwood <[email protected]>
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/errno.h>
#include <linux/interrupt.h>
#include <linux/ioport.h>
#include <linux/init.h>
#include <linux/mutex.h>
#include <linux/clk.h>
#include <linux/err.h>
#include <linux/platform_device.h>
#include <linux/spi/pxa2xx_spi.h>
#include <linux/io.h>

#include <asm/irq.h>
#include <mach/hardware.h>

static DEFINE_MUTEX(ssp_lock);
static LIST_HEAD(ssp_list);

struct ssp_device *pxa_ssp_request(int port, const char *label)
{
    struct ssp_device *ssp = NULL;

    mutex_lock(&ssp_lock);

    list_for_each_entry(ssp, &ssp_list, node) {
        if (ssp->port_id == port && ssp->use_count == 0) {
            ssp->use_count++;
            ssp->label = label;
            break;
        }
    }

    mutex_unlock(&ssp_lock);

    if (&ssp->node == &ssp_list)
        return NULL;

    return ssp;
}
EXPORT_SYMBOL(pxa_ssp_request);

void pxa_ssp_free(struct ssp_device *ssp)
{
    mutex_lock(&ssp_lock);
    if (ssp->use_count) {
        ssp->use_count--;
        ssp->label = NULL;
    } else
        dev_err(&ssp->pdev->dev, "device already free\n");
    mutex_unlock(&ssp_lock);
}
EXPORT_SYMBOL(pxa_ssp_free);

static int __devinit pxa_ssp_probe(struct platform_device *pdev)
{
    const struct platform_device_id *id = platform_get_device_id(pdev);
    struct resource *res;
    struct ssp_device *ssp;
    int ret = 0;

    ssp = kzalloc(sizeof(struct ssp_device), GFP_KERNEL);
    if (ssp == NULL) {
        dev_err(&pdev->dev, "failed to allocate memory");
        return -ENOMEM;
    }
    ssp->pdev = pdev;

    ssp->clk = clk_get(&pdev->dev, NULL);
    if (IS_ERR(ssp->clk)) {
        ret = PTR_ERR(ssp->clk);
        goto err_free;
    }

    res = platform_get_resource(pdev, IORESOURCE_DMA, 0);
    if (res == NULL) {
        dev_err(&pdev->dev, "no SSP RX DRCMR defined\n");
        ret = -ENODEV;
        goto err_free_clk;
    }
    ssp->drcmr_rx = res->start;

    res = platform_get_resource(pdev, IORESOURCE_DMA, 1);
    if (res == NULL) {
        dev_err(&pdev->dev, "no SSP TX DRCMR defined\n");
        ret = -ENODEV;
        goto err_free_clk;
    }
    ssp->drcmr_tx = res->start;

    res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
    if (res == NULL) {
        dev_err(&pdev->dev, "no memory resource defined\n");
        ret = -ENODEV;
        goto err_free_clk;
    }

    res = request_mem_region(res->start, resource_size(res),
            pdev->name);
    if (res == NULL) {
        dev_err(&pdev->dev, "failed to request memory resource\n");
        ret = -EBUSY;
        goto err_free_clk;
    }

    ssp->phys_base = res->start;

    ssp->mmio_base = ioremap(res->start, resource_size(res));
    if (ssp->mmio_base == NULL) {
        dev_err(&pdev->dev, "failed to ioremap() registers\n");
        ret = -ENODEV;
        goto err_free_mem;
    }

    ssp->irq = platform_get_irq(pdev, 0);
    if (ssp->irq < 0) {
        dev_err(&pdev->dev, "no IRQ resource defined\n");
        ret = -ENODEV;
        goto err_free_io;
    }

    /* PXA2xx/3xx SSP ports starts from 1 and the internal pdev->id
     * starts from 0, do a translation here
     */
    ssp->port_id = pdev->id + 1;
    ssp->use_count = 0;
    ssp->type = (int)id->driver_data;

    mutex_lock(&ssp_lock);
    list_add(&ssp->node, &ssp_list);
    mutex_unlock(&ssp_lock);

    platform_set_drvdata(pdev, ssp);
    return 0;

err_free_io:
    iounmap(ssp->mmio_base);
err_free_mem:
    release_mem_region(res->start, resource_size(res));
err_free_clk:
    clk_put(ssp->clk);
err_free:
    kfree(ssp);
    return ret;
}

static int __devexit pxa_ssp_remove(struct platform_device *pdev)
{
    struct resource *res;
    struct ssp_device *ssp;

    ssp = platform_get_drvdata(pdev);
    if (ssp == NULL)
        return -ENODEV;

    iounmap(ssp->mmio_base);

    res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
    release_mem_region(res->start, resource_size(res));

    clk_put(ssp->clk);

    mutex_lock(&ssp_lock);
    list_del(&ssp->node);
    mutex_unlock(&ssp_lock);

    kfree(ssp);
    return 0;
}

static const struct platform_device_id ssp_id_table[] = {
    { "pxa25x-ssp",     PXA25x_SSP },
    { "pxa25x-nssp",    PXA25x_NSSP },
    { "pxa27x-ssp",     PXA27x_SSP },
    { "pxa168-ssp",     PXA168_SSP },
    { "pxa910-ssp",     PXA910_SSP },
    { },
};

static struct platform_driver pxa_ssp_driver = {
    .probe      = pxa_ssp_probe,
    .remove     = __devexit_p(pxa_ssp_remove),
    .driver     = {
        .owner  = THIS_MODULE,
        .name   = "pxa2xx-ssp",
    },
    .id_table   = ssp_id_table,
};

static int __init pxa_ssp_init(void)
{
    return platform_driver_register(&pxa_ssp_driver);
}

static void __exit pxa_ssp_exit(void)
{
    platform_driver_unregister(&pxa_ssp_driver);
}

arch_initcall(pxa_ssp_init);
module_exit(pxa_ssp_exit);

MODULE_DESCRIPTION("PXA SSP driver");
MODULE_AUTHOR("Liam Girdwood");
MODULE_LICENSE("GPL");